1. Technical Field
The present disclosure relates to overload protection mechanisms and, particularly, to an overload protection mechanism used in a shaft coupling device.
2. Description of the Related Art
Industrial robots are widely used in various applications to greatly reduce the burden of factory workers. A manipulator is an important component of the industrial robot. A typical manipulator includes a mechanical arm, a typical shaft coupling device, and a mechanical hand. The typical shaft coupling device interconnects the mechanical arm with the mechanical hand. The typical shaft coupling device includes an overload protection mechanism to protect the manipulator when the mechanical hand is applied to an external, overloaded force. The overload protection mechanism includes a sleeve, a fixing member rotatable sleeved on the sleeve, a plurality of springs, and a plurality of balls. The sleeve is fixed to the mechanical hand, and the fixing member is fixed to the mechanical arm. The fixing member defines a plurality of fixing holes in a side surface thereof, and the sleeve defines a plurality of receiving grooves in a side surface thereof corresponding to the fixing holes. One end of each of the springs is fixedly received in a receiving groove of the receiving grooves, and each of the balls is fixed to the distal end of each of the springs. The diameter of the balls is larger than that of the fixing holes, and is smaller than that of the receiving grooves. The compressed springs press the balls against the fixing holes, thereby the balls are received both in the receiving holes and at least partly in the fixing holes, to achieve non-slip rotation by the mechanical hand. When the mechanical arm is overloaded, the fixing member may move relative to the sleeve, and the fixing holes slide away, so the balls are entirely received in the receiving grooves. Thereby the mechanical arm ceases to drive the mechanical hand in rotation, which provides a protection against overload of the typical shaft coupling device. However, the typical overload protection mechanism used in the manipulator is difficult to automatically return after the overload protection mechanism is released.
Therefore, there is room for improvement within the art.